Hmmm. Thanks. That solves the immediate problem. I am letting my
students choose between Matlab and Python for projects in my course.
This one my erode their confidence in Python/Scipy a bit.
On Thu, Jan 28, 2010 at 3:05 PM, <josef.pktd@gmail.com> wrote:
> On Thu, Jan 28, 2010 at 3:39 PM, Ryan Krauss <ryanlists@gmail.com> wrote:
>> I believe I have discovered a bug in signal.lsim2. I believe the
>> short attached script illustrates the problem. I was trying to
>> predict the response of a transfer function with a pure integrator:
>>>> g
>> G = -------------
>> s(s+p)
>>>> to a finite width pulse. lsim2 seems to handle the step response just
>> fine, but says that the pulse response is exactly 0.0 for the entire
>> time of the simulation. Obviously, this isn't the right answer.
>>>> I am running scipy 0.7.0 and numpy 1.2.1 on Ubuntu 9.04, but I also
>> have the same problem on Windows running 0.7.1 and 1.4.0.
>>>> Thanks,
>>>> Ryan
>> When I add a small noise
>> u2 = zeros(N) + 1e-14
>> or for
> u2[:50] = amp
>> or for
> u2[50:200] = amp
>> it seems to work.
>> This might be a tricky bug.
>> Josef
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